Not applicable.
Not applicable.
The present invention relates to safety apparatus and methods for opening unions used in fluid flowstreams. More particularly, the present invention relates to a threaded union that cannot be opened without first removing a pressure indicating, or relief, device and methods relating thereto.
Various types of fluid flow systems and components relating thereto, such as valves, closures and unions often contain internal pressure(s) that can cause injury to operators and damage to property if the valve, closure, union or another component is disconnected, or opened, without first releasing sufficient internal pressure. Safety devices have been proposed with the goal of preventing premature disconnection, disassembly or opening of the device prior to the release of sufficient pressure.
For example, choke valves are commonly used in high-pressure flow lines, pipelines and other systems in the petroleum industry, such as to regulate the flow of drilling fluid and petroleum, for well testing and well clean-up. It is often necessary or desirable to disassemble such choke valves for various reasons, such as to service the valve, flow line or petroleum well. A typical such choke valve includes a body portion and a removable portion attached thereto. The valve is disassembled by disconnecting the removable portion from the body portion. A releasable pressure bleeder device is often used with such choke valves to indicate the presence, or extent, of internal pressure and possibly also to enable the release of some or all of the internal pressure.
Safety devices have been proposed for choke valves. In U.S. Pat. No. 5,065,787 to Lochmann, for example, a choke valve safety device includes an external support bracket connectable between a removable choke bonnet nut and choke body. The Lochmann patent provides that the choke bonnet nut cannot be removed from the choke body until the support bracket is removed, which requires removal of a pressure bleeder device from the choke body. For another example, U.S. Pat. No. 5,241,980 to Corte, having a common assignee with the present application, discloses a choke valve safety device having an external C-shaped clamp plate for connecting a removable wing nut and the valve body to prevent removal of the wing nut until pressure within the bore of the valve is relieved. For yet another example, the UNIBOLT(copyright) coupling by Thornhill Craver includes a removable yoke nut engageable with a choke valve body with the use of interlocking tapered shelves, or lugs. The yoke nut and valve body are secured in place with an external T-head bolt. The yoke nut engages a removable pressure bleeder plug and cannot be disconnected from the valve body without first removing the T-head bolt and bleeder plug.
With respect to each of the above-cited references, it is important to understand that the features mentioned above are merely examples of features disclosed in the references. Each reference has numerous other features in addition to the features mentioned herein. The additional features can be readily understood from a thorough review of each respective reference. The brief discussion above is included only to introduce the subject matter of the references and not to fully distinguish the same from the present invention. Therefore, it is the patent applicant""s intent that the brief remarks above about the cited references not, in any way, limit or affect the scope of any of the appended claims. A comparison of any of the above-cited references with the invention of any of the appended claims should involve a comparison of all features of the cited reference together as compared to the entirety of the selected claim(s).
In considering existing technology for opening unions used in fluid flowstreams, there remains a need for safety apparatus and/or methods having one or more of the following attributes: an apparatus that does not require additional components; an apparatus that does not require additional external components; an apparatus that does not require bulky components; an apparatus that does not require complex components; an apparatus that is generally reliable in preventing inadvertent, or undesirable, opening of the union; an apparatus that requires, or occupies, minimal additional space in the union, or area within which the union is located; apparatus and methods that can be implemented by modifying, or retrofitting existing unions; apparatus and methods that, in use, do not require additional positive action; an apparatus that adds little or no weight to the union; apparatus, the components of which can be mass-produced and interchangeable; an apparatus that is cost effective to manufacture, assemble and use; an apparatus that is simple and durable in construction and use.
In accordance with the present invention, certain embodiments involve a union assembly useful in a fluid flowstream and having a body portion, a pressure indicating device and a removable cover. The body portion includes a bore, an access opening and a pressure indicating device cavity in fluid communication. The body portion further includes a first plurality of threads disposed around the access opening. The pressure indicating device cavity is disposed proximate to the first plurality of threads. The pressure indicating device is releasably engageable within the pressure indicating device cavity. The removable cover includes a passageway and a second plurality of threads disposed around the passageway. Engagement of the first and second pluralities of threads will secure the removable cover in connection with the body portion for use of the union assembly without the need for any additional mechanism connecting the removable cover with the body portion. The removable cover further includes a cut-out portion disposed proximate to the second plurality of threads, whereby when the removable cover and the pressure indicating device are engaged with the body portion, the cut-out portion is disposed at least partially around the pressure indicating device, and the pressure indicating device must be disengaged from the body portion before the removable cover may be disconnected from the body portion.
The first and second pluralities of threads may each include a beginning thread, whereby the start points of the beginning threads of the first and second pluralities of threads are disposed on the body portion and the removable cover, respectively, in such a manner as to enable the cut-out portion of the removable cover to align over the pressure indicating device cavity of the body portion when the removable cover and the body portion are threadably engaged. The pressure indicating device cavity may be located on the circumference of the body portion relative to the start point of the beginning thread of the first plurality of threads, and the cut-out portion may be located on the removable cover relative to the start point of the beginning thread of the second plurality of threads to enable the cut-out portion of the removable cover to align over the pressure indicating device cavity of the body portion when the removable cover and the body portion are threadably engaged. Further, the removable cover may be threadably engaged and disengaged with the body portion by pneumatic actuation.
A plurality of the body portions and a plurality of the removable covers may be included, whereby any among the plurality of removable covers is threadably engageable with any among the plurality of body portions and each cut-out portion of the plurality of removable covers will be disposed over the respective pressure indicating device cavity of the body portion with which the respective removable cover is engaged. The cut-out portion may be formed to allow variation in the location of the start point of the beginning thread of each of the first and second pluralities of threads. The removable cover may be a wing nut and the cut-out portion may be a recess that occupies approximately sixty degrees of the circumference of the wing nut. The union assembly may be useful in a high pressure fluid flowline. The union assembly may be a choke valve, the body portion being a choke valve body and the removable cover being a wing nut. The pressure indicating device may be a bleeder plug. The union assembly may be useful in a heating apparatus and/or during petroleum well cleanup operations.
In another embodiment, a choke valve safety device is useful in a high pressure fluid flow line and includes a valve body having a plurality of male threads and a pressure vent plug orifice disposed in the valve body proximate to the plurality of male threads. A wing nut having a plurality of female threads threadably engageable with the plurality of male threads of the valve body is also included, the wing nut further having a recess proximate to the plurality of female threads. The wing nut at least partially surrounds the pressure vent plug orifice when the wing nut and the valve body are threadably engaged. No further connection mechanism is necessary for connecting the wing nut with the valve body.
Certain embodiments involve a method for opening a union assembly disposed in a high pressure fluid flowline with the use of a union body having a pressure indicating device cavity, a pressure indicating device engageable in the pressure indicating device cavity, a removable cover threadably engageable with the union body that includes threadably engaging the removable cover with the union body and installing the pressure indicating device in the pressure indicating device cavity. The pressure indicating device is loosened from the pressure indicating device cavity and pressure is released from the union body portion. The pressure indicating device is removed and the removable cover is threadably disengaged from the body portion.
Certain embodiments involve a method for forming a union assembly that cannot be opened prior to releasing sufficient pressure in the union assembly, the union assembly having a union body and a removable cover, the union body having a bore and an access opening, the removable cover having a passageway, includes forming a pressure indicating device cavity in the union body and a cut-out portion in the removable cover. A plurality of male threads is formed around the access opening of the union body proximate to the pressure indicating device cavity, the start point of the beginning thread of the plurality of male threads being located on the union body between approximately 165 degrees and approximately 195 degrees from the centerline of the pressure indicating device cavity to enable alignment of the cut-out portion of the removable cover over the pressure indicating device cavity when the removable cover and the union body are threadably engaged. A plurality of female threads is formed around the passageway of the removable cover proximate to the cut-out portion, the start point of the beginning thread of the plurality of female threads being located on the removable cover between approximately 165 degrees and approximately 195 degrees from the centerline of the cut-out portion to enable alignment of the cut-out portion over the pressure indicating device cavity of the union body when the removable cover and the union body portion are threadably engaged.
Accordingly, the present invention includes features and advantages which enable it to substantially advance the technology associated with unions that can be disassembled or opened. Characteristics and advantages of the present invention described above, as well as additional features and benefits, will be readily apparent to those skilled in the art upon consideration of the following detailed description of preferred embodiments and referring to the accompanying drawings.